Developmental delays and disorders are not uncommon and affect 10 to 20% of children under the age of 5. Early identification of children with delays allows referral for assessment and appropriate intervention, which can influence the child’s developmental trajectory, allowing optimisation of his potential. The family physician has a very important role to play in monitoring the development of children under his care. He is well placed to do this in a longitudinal sense, as he already has an ongoing relationship with the family, and has many opportunities repeated contact with the child in the first few years of life. Developmental surveillance using the checklists, limit milestones and red flags in the Child Health Booklet is described.